It is known to provide a heater pad at a rear surface of a reflective element of an exterior rearview mirror assembly of a vehicle. Such heater pads are typically adhered to the rear surface of the reflective element, such as via double sided adhesive tape of the like. The heater pad includes two conductive traces disposed thereon and often includes electrical connectors or contacts protruding therefrom for electrical connection of the conductive traces to a power source or wiring harness of the mirror assembly. When the connectors are powered, the conductive traces generate heat. Such heater pads are typically applied to the rear surface of the reflective element that is unobstructed by other elements at the rear surface, such that the heater pad may be adhered directly to the rear glass surface of the glass reflective element.